1. Field of the Invention
The present invention relates to an apparatus and a method for replacing a working-object such as a metal mold, a work pallet and the like for a processing machine such as an injection molding machine, a press machine, a machining center and so on.
2. Description of the Prior Art
Such an apparatus for replacing a working-object of a processing machine is disclosed, for instance in a conventional embodiment as shown in FIGS. 19 through 21 (refer to Japanese Provisional Utility Model Publication No. 1986-47611) and has a following basic construction.
That is, a metal mold replacing apparatus 302 of an injection molding machine 301 as a processing machine comprises a working-object replacing support 306 on which working-objects 304, 305 can be placed, working-object moving passages 312, 313 arranged on the replacing support 306 so as to extend in the fore and back direction and push/pull drive means 317, 318 for pushing and pulling the respective working-objects 304, 305 in the fore and back direction (in the direction indicated by arrows F, B) so as to bring in and bring out them with respect to the injection molding machine 301.
Each push/pull drive means 317, 318 comprises a push/pull drive device 319, a push/pull engaging member pedestal 320, a push/pull transmission member 321 composed of a bendable storable chain, a guide rail 322 provided for guiding the pushing and the pulling of both the push/pull transmission member 321 and the engaging member pedestal 320 and a push/pull engaging member 323 supported by the engaging member pedestal 320.
The push/pull drive device 319 is fixedly secured to the back portion of the replacing support 306 and adapted to drive the engaging member pedestal 320 in the fore and back direction through the push/pull transmission member 321. The engaging member 323 is movable so as to be changed over between the engagement position where it is engaged with respective engaged portions 325 of the metal molds 304, 305 and the disengagement position where the engagement thereof is cancelled.
In the above-mentioned basic construction, conventionally the portion for engaging and disengaging the engaging portion 359 of the engaging member 323 with respect to the respective engaged portions 325 is constructed as follows.
That is, the respective metal molds 305, (304) are provided at their lower portions with the engaged portions 325 composed of upward opened grooves and projected horizontally. The engaging member 323 is supported vertically pivotably by the engaging member pedestal 320 and is provided at its foreside end with the engaging portion 359 projected downward. The engaging portion 359 is adapted to be engaged with and disengaged from the engaged portion 325 from above.
There are, however, following problems associated with the above-mentioned conventional embodiment.
For example, when the metal molds 304, 305 are brought in and brought out with respect to metal mold receiving surfaces 315, 316 by utilizing an overhead travelling crane or a fork lift, it is apprehended that the engaging member pedestal 320 and the engaging member 323 are damaged by the engaged portions 325 of the metal molds 304, 305 swung and brought into contact therewith during the lifting up because the engaging member pedestal 320 and the engaging member 323 are projected upward from the upper surface of the replacing support 306. Therefore, the operations of the crane and the fork lift become complicated, and the replacement of the metal mold is troublesome.
In order to prevent the engaging member pedestal 320 and the engaging member 323 from being conflicted with the metal mold and the engaged portion 325 thereof when the metal mold is placed onto the metal mold replacing support 306 by means of the crane and the like, it is necessary to retreat both the engaging member pedestal 320 and the engaging member 323 behind the metal mold replacing support 306. Therefore, since the metal mold replacing support 306 has to be made longer corresponding to the retreating distance, it becomes large in size and heavy in weight.
Further, according to the conventional embodiment, the distance L between the height position where the guide rail 322 guides the engaging member pedestal 320 and the height position where the engaging member 323 engages with the engaged portion 325 is large. Therefore, the moment disposed to turn the engaging member pedestal 320 in the vertical direction relative to the guide rail 322 becomes large due to the reaction force produced when the metal mold is pushed and pulled thereon. As a result, the guide rail 322 is required to have a sufficient strength bearable against the large moment, and further the metal mold replacing support 306 becomes larger in size and heavier in weight.